What Is A PBX?
Also known as an IP PBX, Unified Communications System or business phone system, a PBX acts as the central switching system for phone calls within a business. PBX systems handle internal traffic between stations and act as the gatekeeper to the outside world. The initials PBX stand for Private Branch Exchange, a very old fashioned term for a system that has evolved significantly over the past century.
A traditional PBX is made up of two key elements: lines and stations. The lines, sometimes called trunks, are connections to the global public switched telephony network (PSTN) by way of a telephone company. Stations are simply telephones or other endpoint devices like fax machines, modems and credit card terminals.
The original mission of the PBX was to provide shared access to limited resources. Rather than having a separate phone line for each phone, a business could share a small pool of lines across a much larger pool of stations. When a call came it was answered by an operator who then connected it with the appropriate person or department. When someone inside needed to make a call, the operator connected them with an available line. Frequently these early systems were simply called “switchboards”.
Over time, operators were replaced by electromechanical and later electronic systems for managing access to lines. Additional features were added to automatically route incoming calls, to allow active calls to be transferred between stations and to permit or deny calls based on various rules. Adjunct systems were added for voice messaging, call queuing and other value added services.
Today, a business phone system is much more than just a simple switch. Adjunct technologies like automated attendant, voice messaging, call queuing and multi-party conferencing have become standard features. Basic analog and proprietary digital phones are giving way to standards-based IP phones. Outside connectivity is now available over the Internet in the form of SIP trunks or other VoIP services.
When PBXs were originally developed, wireline phone calls were the only type of electronic communication available. Today, the communications landscape has expanded to include email, instant messaging, video conferencing, desktop sharing, SMS and mobile telephony. Unified Communications is a catch-all term that describes the process of merging all of these technologies and integrating them with business processes. Unified Communications aims to increase efficiency while simplifying management.
Key PBX Features
If you’re looking for a PBX, here are some of the features you should be sure are included:
VoIP Ready: The world is moving away from legacy PSTN lines and towards VoIP. Make sure your PBX can support IP stations (phones) and IP trunks (service). SIP is the current de facto standard, so don’t buy a phone system that doesn’t support it.
Voice Messaging: Once upon a time, voicemail was an optional add-on. Today, it’s table stakes. Look for PBXs that can forward voicemail messages to your email as attachments. If possible, look for IP phones that support visual voicemail.
Mobility: Most businesses have at least some road warriors who spend much of their time out of the office. Make sure your PBX supports mobility features like Find Me / Follow Me, remote IP extensions and fixed / mobile convergence.
Conferencing: One of the best ways to cut down on travel costs is teleconferencing. Make sure your phone system has native support for true multi-party conferences (not just basic three-way calling).
Reporting: If you can’t measure it, you can’t manage it. Make sure that the PBX you pick includes basic call history reporting features.
Asterisk As A PBX
Asterisk was originally created as the engine for a PBX system (in fact, many refer to it as the Asterisk PBX) and includes all of the components necessary to build a powerful, scalable business phone system. These include advanced features that usually cost extra on a commercial phone system: things like voicemail, automated attendant, call queueing, conference bridging, parking, paging, and intercom calling.
Asterisk is technology and protocol agnostic, which means that you can connect it to the outside world using VoIP or traditional telephony technologies. It also means that you can use virtually any standards-based IP phone; Asterisk includes drivers for SIP and other protocols. That being said, Digium offers a line of IP phones that were specifically designed to compliment Asterisk and take advantage of a number of key productivity features.
Asterisk is future-proof. Unlike traditional phone systems that are generally upgraded using a forklift, Asterisk continues to evolve. Phone systems based on Asterisk see significant improvements each year as new features are included.
Build From Scratch
There are several options for building a PBX system using Asterisk. You can build a completely custom solution from scratch, starting with just the raw Asterisk engine. This gives you complete control over the way your phone system operates, but requires a good deal of effort and can be difficult to maintain unless you have an Asterisk expert on staff. Building from scratch is appropriate if you are creating a new product or service, if your project has extremely specific requirements that cannot be met with off-the-shelf solutions, or if you simply enjoy the challenge of learning a new skill.
Build From A Distro
Another DIY option (with a significantly lower learning curve) is to deploy a software appliance like AsteriskNOW. AsteriskNOW is a special Linux distribution that installs the operating system, Asterisk, drivers for Digium telephony cards and phones and an open source administrative user interface called FreePBX. The installation process if fully automated and takes roughly 20 minutes to convert a computer into a working phone system.
Buy A Turnkey Solution
Digium offers a turnkey PBX system based on Asterisk. The product, called Switchvox, combines the core Asterisk engine with an intuitive user interface and advanced Unified Communications features like instant messaging, universal inbox and fixed / mobile convergence. Priced at a fraction of what you would pay for a traditional phone system, Switchvox is the best of both worlds.
Learn more about VoIP PBX software by Digium powered by Asterisk.